Telechelic copolymers of dienes and polymerizable ferrocene or carborane compounds

ABSTRACT

Copolymers of a diene selected from butadiene, isoprene, and chloroprene and a polymerizable monomer selected from ferrocenylmethyl methacrylate, isopropenylferrocene, 1ferrocenylbutadiene, 2-ferrocenyl-butadiene, vinylcarborane, isopropenylcarborane and carboranylmethyl acrylate are disclosed along with preparative procedures therefor. Copolymerizations are carried out in solution (toluene or dioxane) with a suitable polymerization initiator selected from an azo compound to introduce either carboxyl or hydroxyl functionality into the copolymers.

1J11e States Reed, 1r.

[ 1 TELECHELIC COPOLYMERS OF DIENES AND POLYMERIZABLE FERROCENE OR CARBORANE COMPOUNDS [76] Inventor: Samuel F. Reed, Jr., 49 Brookside Dr., Holland, Pa. 18966 [22] Filed: June 18, 1971 [2]] Appl. No.: 155,669

[52] 11.8. C1 260/82.1, 260/835, 260/863, 260/439 CY, 260/6065 B, 149/192 [51] Int. Cl. C081 19/00 [58] Field of Search 260/439 CY, 83.5, 85.3 R, 260/853 C. 82.1, 86.3, 606.5 B; 149/192 [56] References Cited UNITED STATES PATENTS 3.146.260 8/1964 Ager et a1. 149/22 UX 3,183,216 5/1965 Cohen ct a1..... 149/22 UX 3.301.836 1/1967 Green et a1 149/22 X 3.518.241 6/1970 Duling et a1. 260/895 3.586.552 6/1971 Potts Ct 211 149/20 X 3.718.633 2/1973 Baldwin et a1. 149/19 FOREIGN PATENTS OR APPLICATIONS 601.243 7/1960 Canada 260/439 CY OTHER PUBLICATIONS Bamford et :11, Trans. Faraday Soc. 56, 93242 1 June 11,1974

(1960) TK 1 F 25 Horspool et al., Can. .1. Chem, 47, 3805-8 (1969) QD 1 C 2 Van Landuyt et al., J. Polymer Science. Part A1, 9, 523-529 (1971) OD 281 P6 .1 62

Primary Examiner-Benjamin R. Padgett Assistant Examiner-13. A. Miller Attorney, Agent, or Firm-Edward J. Kelly; Herbert Berl; Jack W. Voigt [57] ABSTRACT 7 Claims, No Drawings TELECHIEILIC COPOILYMIERS 01F DIENES AND POLYMERIZABLIE FERROCENE OR CARBOIRANE COMPOUNDS BACKGROUND OF THE INVENTION Considerable literature exists on the preparation of polydienes of the telechelic type prepared by both anionic and free radical initiators.

Well known in the propellant field is the fact that the burning rate of many solid propellants can be increased by the introduction of certain additives. Many ferrocene or carborane derivatives have been utilized as additives for this purpose, usually in the form of liquids in which state they also serve as plasticizing agents. In the liquid state the additives exhibit the inherent disadvantages characteristic of liquid additives such as loss by evaporation, migration, etc., and consequently, the propellant systems suffer, particularly on long term storage.

Thus, a need exists for a modified form of ferrocene or carborane additive which form is not subject to being lost by evaporation or migration from a stored propellant composition.

An object of this invention is to combine a selected l'erroccnc or curboranc additive with the binder being utilized in the propellant system.

Another object is to combine the selected ferrocene or carborane additive and the binder material via a po lymerization technique into a serviceable prepolymer suitable for propellant mixing and curing.

A specific object of this invention is to copolymerize a binder material and a catalyst material to provide a liquid copolymer which is capable of undergoing a cure reaction when used in a propellant composition to form a rubber-like binder material having a burning rate catalyst agent as an integral part thereof.

SUMMARY OF THE INVENTION Copolymers of dienes selected from butadiene, isoprene, and chloroprene and polymerizable monomers selected from ferrocenylmethyl methacrylate (FMMA), isopropenylferrocene (IPF), 1-

ferrocenylbutadiene (l-FB), Z-ferrocenylbutadiene (21 13), vinylcarborane (VC), isopropenylcarborane (IPC), and carboranylmethyl acrylate (CMA) are prepared through free radical copolymerization in an inert organic solvent (e.g., toluene or dioxane) using an azo compound initiator selected from azobis (2-methyl valeric acid) (AIVlCV), 4,4-azobis (4cyanopentanoic acid) (ACPA), and 4,4-azobis (4cyano-n-pentanol) (HMHV). The reaction periods may vary from about 72-96 hours while the reactor is maintained at temperature from about 6667C. Comonomer weight ratios may be varied from about 1:1 to about 19:1 (diene to monomer weight ratio). Physical properties of the copolymers may best be controlled by varying the initiator concentration. The copolymers are characterized by molecular weights in the range from about 1,500 to about 10,000, and end group (CO H or OH) from about 0.1 to about 5.0 weight percent. Boron contents of the copolymers may be varied. from about 30 weight percent; iron contents of the copolymers may be varied from about 0-15 weight percent.

DESCRIPTION OF THE PREFERRED EMBODIMENTS ration is set forth below for the diene, butadiene, and

the monomer, carboranylmethyl acrylate (CIVIA). Following this descriptive technique will be Tables lVlIl which illustrate the experimental data on preparation of other copolymers and physical property data for the particular copolymers set forth.

A general descriptive technique employed in the copolymerization of butadiene and CMA and used in all other copolymerizations is as follows: to a glass highpressure reactor (aerosol tube) are introduced 30 ml of dioxane, 1.0 g (3.34 mmoles) CMA and 3.28 g (10.7 mmoles) azobis (Z-methyl valeric acid) (AIVICV). The reactor is attached to a vacuum line and deaerated by three alternate freeze-thaw cycles. At this point 19.0 g (352 mmoles) of butadiene are condensed into the reactor, and the reactor is removed from the vacuum line and placed in an oil bath at 6667C. l-Ieating is continued for a period of 72 hours. On cooling, the reactor is vented, the solvent removed by evaporation, and the copolymer reprecipitated by dissolving in ether followed by the addition of methanol. After decanting the solvents, the copolymer is stripped of excess solvents on a rotary evaporator, and finally dried at 70-75C. under reduced pressure (1 mm) for a period of 24 hours. The liquid copolymer is then. characterized by its molecular weight, hydroxy-end group content and elemental analysis. These values are: molecular weight 3,500, carboxyl-end group content 2.56, boron 2.55 percent (calculated 2.37 percent).

The experimental data for examples of other copolymerizations are given in the following Tables (l-Vlll). Comonomer weight ratios are varied from approximately 1:1 to 19: 1. Physical properties of the copolymers may best be controlled by varying the initiator concentration. It is reasonable to expect molecular weights in the range of l,500-10,000 and end group (CO H or 0H) from 0.1 to 5.0. Boron contents of the copolymers may be varied from 030 weight percent; iron content from 0-15 weight percent.

COPOLYMERS OF BUTADIENE CIVIA TABLE I EXPERIMENTAL DATA ON PREPARATION OF BUTADlENE-CMA COPOLYMERS [Temperature "72 hours] TABLE 11 PHYSICAL PROPERTY DATA ON BUTADlENE/CMA COPOLYMERS TABLE Vlll PHYSICAL PROPERTY DATA ON BUTADIENE/ 1 -FB COPOLYMERS No. Molecular Weight COH "/0 B No. Molecular Weight Fe Weight (M 1 Found Calculated Weight n) CO H Calculated Found COPOLYMERS OF ISOPRENE FMMA The effectiveness of copolymers of this invention as TABiE'I'iT" EXPERlMENTAL DATA FOR PREPARATION OF lsoPRENE-FMMA COPOLYMERS lsoprene FMMA AMHV Molar ratio Solvent Weight co- Yield No g. (moles) g. (moles) g. (moles) isoprene/ (30 ml.) polymer (g) (percent) FMMA 5 19 (352) l (3.5) 2.69 (10.7) 100.5 Dioxane 12.5 63.5 6 17 (315) 3 (10.5) 2.46 (9.8) 30.0 Dioxane 11.7 58.5 7 (277) 5 (17.5) 2.23 (8.8) 15.8 Dioxane 15.0 75.0 8 v 10 185) 10 (35) 1.66 (6.6) 5.3 Dioxane 17.6 88.0

TABLE IV a binder-burning rate catalyst is illustrated by combin- PHYSCAL PROPERTY D AT A ON ing the copolymer with a plasticizer, a metal additive, lSOPRENE/FMMA COPOLYMERS and an morgamc oxidizer. A test propellant composition comprised of a selected copolymer having about a Nu Molecular weight); OH I Fe 1 weight percent iron (Fe) or a selected copolymer Weight Calculated Found having about a 1 weight percent boron (B) will provide 5 3300 120 02 M an increase of at least 20 percent in the burning rate as 6 3800 0.78 3.08 2.5 compared with a standard propellant composition hav- 7 4400 ing a diene binder which does not contain iron or boron. The test propellant composition described above COPOLYMERS OF BUTAD1ENE- contained about 10 weight percent copolymer, l0 ISOPROPENYLFERROCENE (lPF) weight percent plasticizer (isodecyl pelargonate), 10

TAEFFV EXPERIMENTAL DATA lfOR BBERAEA TIQIiL EBlJTADI N COPOLYMERS [Temperature 65 C.Time: 72 hours] Butadiene(Bd) IPF AMHV Molar ratio Solvent Weight 00- Yield No. g. (mmoles) g. (mmoles) g. (mmoles) Bd/IPF (30 ml.) polymer (g) (percent) 9 19 352 1 4.4) 2.991107) 79.64 E6361} 14.4 72.2 l0 17 (315) 3 (13.2) 2.74 (9.8) 23.74 Dioxane 13.0 65.0 ll 15 (277) 5 (22) 2.52 (8.99) 12.52 Dioxane 15.4 75.2 l2 10 (185) 10 (44.1) 1.93 (6.88) 4.18 Dioxane 14.4 72.2

TABLE VI weight percent metal additive (aluminum powder), and PHYSICAL PROPERTY DATA ON up to about 7l(1)lwe1ght percent 1norgan1cox1d1zer (am- BUTADlENE/IPF COPOLYMERS mcmlum Pm 01am The copolymers of th1s invention may be used 1n NO. Molecular Weight "/1 011 "/1 Fe varying amounts from about 5 to about 30 weight pere g (M..) cfllculuted Fmmd cent of the propellant composition. Since the weight 0 3100 2.94 1.24 1,4 percent of the metallic containing monomer can also 10 2600 3.03 3.71 3.4 H 2600 240 62' 53 be varied over a w1de range 1n preparmg the copoly- 1 @300 L50 1139 M mer, propellant compos1t10ns havmg a w1de range of burning rates can be prepared using the copolymers of TABLE v11 EXPERIMENTAL DATA FOR PREPARATION OF BUTADIENE- 1-FB COPOLYMER [65 C 72 hours] Butadiene(Bd) l-FB AMCV Molar ratio Solvent Weight co- Yield No g. (mmoles) g. (mmoles) g. (mmoles) Bd/l-FB (30 ml) polymer (g) (percent) 13 19 352) 1 4.2) 2.9967107) 83.8 Dioxane 13.7 68.5 14 17 315 3 (12.6) 2.744 (9.8) 25.0 Dioxane 10.5 50.2 l5 15 (277) 5 (21) 2.24 (9) 13.2 Dioxane 7.5 37.5 16 10 10.0 (42 1.904 (6.8) 4.4 Dioxane 5.2 26.0

this invention. Also, on the basis of requirements, copolymers may be prepared which contain the iron catalyst component or the boron catalyst component. The burning rates of propellant compositions vary with an increase in the metal content of the catalyst-binder copolymers contained in the propellant compositions. Catalysts compounds containing iron, boron, or combinations thereof have been proven to be effective catalysts; however, the use of these metal compounds in a curable rubber-like polymer makes them even more attractive due to stability from migration, improvement to physical properties, etc. Other plasticizers, metal additives, or oxidizing salts may be used with the copolymers of this invention since these copolymers are compatible and curable with a wide variety of propellant ingredients.

1 claim:

1. Copolymers of a diene selected from butadiene, isoprene, and chloroprene and a polymerizable monomer selected from ferrocenylmethyl methacrylate, 1 ferrocenylbutadiene, vinylcarborane, and isopropeny1 carborane prepared by reacting said polymerizable monomer and a suitable polymerization initiator in an inert organic solvent with said diene at a reaction temperature and for a reaction period sufficient for said reaction to take place after which solvent removal is effected and said copolymers are dried at a suitable drying temperature while under reduced pressure; said initiator being selected from the azo initiators consisting of azobis(2-methyl valeric acid), 4,4"azobis(4- cyanopentanoic acid), and 4,4-azobis(4-cyano-npentanol); said inert organic solvent being selected from dioxane and toluene; said reaction temperature being from about 6667C.; said reaction time being from about 72-96 hours; said drying is accomplished at a suitable temperature in the range of about 70C. to about 75C. and said reduced pressure is in the range of about 1 millimeter; said copolymers being characterized by molecular weights in the range from about 1,500 to about 10,000.

2. The copolymers prepared by the reaction of claim 1 wherein said polmerizable monomer is selected from fe rrocenylmethyl methacrylate, and 1- ferrocenylbutadiene and wherein weight ratios of said diene to said polymerizable monomer is varied from about 1:1 to about 19:1 and wherein said copolymers are further characterized by having an iron content up to about weight percent.

3. The copolymers of claim 2 wherein said diene selected is isoprene; said polymerizable monomer selected is ferrocenylmethyl methacrylate; said initiator selected is 4,4' azobis(4-cyano-n-pentano1); and wherein said copolymers are still further characterized by having a molecular weight from about 3,300 to about 4,400, a weight percent of OH terminal groups from about 0.25 to about 1.20, and a weight percent Fe from about 1.1 to about 6.3.

4. The copolymers of claim 2 wherein said diene selected is butadiene; said polymerizable monomer selected is 1-ferrocenylbutadiene; said initiator selected is azobis(2-methyl valeric acid); and wherein said copolymers are still further characterized by having a molecular weight from about 1,900 to about 2,800, a weight percent of C0 11 terminal groups from about 3.20 to about 4.33, and weight percent Fe from about 2.0 to about 15.

5. The copolymers prepared by the reaction of claim 1 wherein said polymerizable monomer is selected from vinylcarborane and isopropenylcarborane and wherein weight ratios of said diene to said polymerizable monomer is varied from about 1:1 to about 19:1 and wherein said copolymers are further characterized by having a boron content up to about 30 weight percent.

6. Copolymers of a diene selected from butadiene, isoprene, and chloroprene and carboranylmethyl acrylate; said copolymers being the carboxyl terminated copolymers that are prepared by reacting said carboranylmethyl acrylate and a suitable polymerization initiator in an inert organic solvent with said diene at a reaction temperature and for a reaction time period sufficient for said reaction to take place after which solvent removal is effected and said copolymers are dried at a suitable drying temperature while under reduced pressure; said initiator being selected from the azo initiators consisting of azobis(2-methyl valeric acid), and 4,4- cyanopentanoic acid) to introduce carboxyl functionality into said copolymers; said inert organic solvent being selected from dioxane and toluene; said reaction temperature being from about 6667C.; said reaction time being from about 72-96 hours; said drying is accomplished at a suitable temperature in the range of about C. to about 75C. and said reduced pressure is in the range of about 1 millimeter; said diene and said carboranylmethyl acrylate being reacted in weight ratios from about 1:1 to about 19:1; said copolymers being characterized by molecular weights in the range from about 1,500 to about 10,000, a CO l-l end group from about 0.1 to about 5 weight percent, and by a boron content up to about 30 weight percent of said copolymers.

7. The copolymers prepared by the reaction of claim 6 wherein said diene selected is butadiene; said initiator selected is azobis (Z-methyl valeric acid); and wherein said copolymers are still further characterized by having a molecular weight from about 2,500 to about 3,500, a weight percent of CO H terminal groups from about 1.45 to about 2.56, and a weight percent boron from about 2.55 to about 20.

umwn s'm'ms P 'aicN'n OFFICE CERTWEQATE 0F CORRECHQN Patent No. '3 816 Dated June 11 1974 lnventofls) Samuel F. Reed, Jr.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

The assignee should read The United States of America as represented by the Secretary of the Army Signed and sealed this 12th day of November 1974.

(SEAL) Attest:

MCCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents FORM P -1 USCOMM-DC 60376-P69 U 5 GOVERNMENT P RINYING OFFICE: 9. 930

UNE'EED STATES PA'EB'IN'B OFFICE CERTIFEQATE 0F CORRECTION Patent No, 3,816,380 Dated June 11, 1974 1 lnventofls) Samuei F. Reed, Jr.

It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

The assignee should read The United States of America as represented by the Secretary of the Army Signed and sealed this 12th day of November 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents F RM P 0 0 (1 USCOMH-DC scan-Pee U S. GOVEINIKNT P RHITING OFHCE: 930 I 

2. The copolymers prepared by the reaction of claim 1 wherein said polmerizable monomer is selected from ferrocenylmethyl methacrylate, and 1-ferrocenylbutadiene and wherein weight ratios of said diene to said polymerizable monomer is varied from about 1:1 to about 19:1 and wherein said copolymers are further characterized by having an iron content up to about 15 weight percent.
 3. The copolymers of claim 2 wherein said diene selected is isoprene; said polymerizable monomer selected is ferrocenylmethyl methacrylate; said initiator selected is 4,4''-azobis(4-cyano-n-pentanol); and wherein said copolymers are still further characterized by having a molecular weight from about 3,300 to about 4,400, a weight percent of OH terminal groups from about 0.25 to about 1.20, and a weight percent Fe from about 1.1 to about 6.3.
 4. The copolymers of claim 2 wherein said diene selected is butadiene; said polymerizable monomer selected is 1-ferrocenylbutadiene; said initiator selected is azobis(2-methyl valeric acid); and wherein said copolymers are still further characterized by having a molecular weight from about 1,900 to about 2,800, a weight percent of CO2H terminal groups from about 3.20 to about 4.33, and weight percent Fe from about 2.0 to about
 15. 5. The copolymers prepared by the reaction of claim 1 wherein said polymerizable monomer is selected from vinylcarborane and isopropenylcarborane and wherein weight ratios of said diene to said polymerizable monomer is varied from about 1:1 to about 19:1 and wherein said copolymers are further characterized by having a boron content up to about 30 weight percent.
 6. Copolymers of a diene selected from butadiene, isoprene, and chloroprene and carboranylmethyl acrylate; said copolymers being the carboxyl terminated copolymers that are prepared by reacting said carboranylmethyl acrylate and a suitable polymerization initiator in an inert organic solvent with said diene at a reaction temperature and for a reaction time period sufficient for said reaction to take place after which solvent removal is effected and said copolymers are dried at a suitable drying temperature while under reduced pressure; said initiator being selected from the azo initiators consisting of azobis(2-methyl valeric acid), and 4,4''-cyanopentanoic acid) to introduce carboxyl functionality into said copolymers; said inert organic solvent being selected from dioxane and toluene; said reaction temperature being from about 66*-67*C.; said reaction time being from about 72-96 hours; said drying is accomplished at a suitable temperature in the range of about 70*C. to about 75*C. and said reduced pressure is in the range of about 1 millimeter; said diene and said carboranylmethyl acrylate being reacted in weight ratios from about 1:1 to about 19:1; said copolymers being characterized by molecular weights in the range from about 1,500 to about 10,000, a CO2H end group from about 0.1 to about 5 weight percent, and by a boron content up to about 30 weight percent of said copolymers.
 7. The copolymers prepared by the reaction of claim 6 wherein said diene selected is butadiene; said initiator selected is azobis (2-methyl valeric acid); and wherein said copolymers are still further characterized by having a molecular weight from about 2,500 to about 3,500, a weight percent of CO2H terminal groups from about 1.45 to about 2.56, and a weight percent boron from about 2.55 to about
 20. 